• High efficient adenoviral-mediated VEGF and Ang-1 gene delivery into osteogenically differentiated human mesenchymal stem cells.

      Klöpper, Jonas; Lindenmaier, Werner; Fiedler, Ulrike; Mehlhorn, Alexander; Stark, G Björn; Finkenzeller, Günter; Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany. (2008-01)
      Survival of ex vivo constructed tissues after transplantation is limited by insufficient oxygen and nutrient supply. Therefore, strategies aiming at improvement of neovascularization of engineered tissues are a key issue in tissue engineering applications. This in vitro study aimed at exploring the usability of osteogenically differentiated human mesenchymal stem cells (MSCs) as carriers of the angiogenic growth factor genes vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) for therapeutic angiogenesis in bone tissue engineering. The ex vivo adenoviral vector mediated transduction into osteogenically differentiated MSCs revealed a highly efficient and long lasting expression of the transgenes. Biological activity of VEGF and Ang-1 secreted from transduced cells was confirmed by analyzing the sprouting, proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) in response to conditioned medium obtained from transduced cells. The transduced osteogenically differentiated MSCs described in this report may be suitable for inducing neovascularization in bone tissue engineering applications.
    • Screening of photochemically grafted polymer films for compatibility with osteogenic precursor cells.

      Adden, Nina; Hoffmann, Andrea; Gross, Gerhard; Windhagen, Henning; Thorey, Fritz; Menzel, Henning; Institut für Technische Chemie, Abt. TC Makromolekularer Stoffe, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, D-38106 Braunschweig, Germany. (2007)
      Surfaces of biomaterials often do not have the ideal properties for direct application in vivo. Although titanium and its alloys show a good biocompatibility, in some applications there is still need to improve the osteoblast adhesion to titanium implants. A polymeric surface coating is an ideal solution because the polymer can be adjusted to the needs of the application and can be bound to the surface by the photochemical grafting method. Therefore, 22 different polymers were tested for their compatibility using a murine mesenchymal progenitor cell line and three polymers were identified for which more elaborate investigations are reasonable. It was investigated whether or not the results of the cell culture test can be correlated with, e.g., the wetting properties. Indeed it was found that a contact angle above approx. 45 degrees was necessary for good cell adhesion and proliferation. However, otherwise no clear correlation between the contact angle hysteresis or the functionalities of the polymers and the cell growth was observed.